Variable speed rotary pump and motor hydraulic transmission



Aug. 14, 1951 Filed June 11 1945 R. S. SEGSWORTH VARIABLE SPEED ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION 4 Sheets- Sheet 1 1951 R. s. SEGSWORTH 2,564,237

A IABLE SPEED R T RY PUMP AND TOR HYDRAULIC ANSMISSION Filed June 11, 1945 4 Sheets-Sheet 2 a k K M ////////ffi 4 1951 R. s. SEGSWORTH 2,564,237

' VARIABLE SPEED ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Filed June 11, 1945 4 Sheets-Sheet 4 InVn/vn I Patented Aug. 14, 1951 LUINH'EED STATES OiFiF-ICLLE VARIABLE SPEED ROTARYPUMRAND 'MOTOR'HYDRAULIC.TRANSMISSION "Robert s. :Segsworth, Toronto, email Ganada,

assignorv to. The General Engineeringvflompany (Canada) Limited; TorontmDDtario, Canada iiApp'lication' June '11, 1945; Se1-ial 1N0598862 (Cl.;B0- -53) 2 Claims.

rotors to effect variation in; speed .isefieotedhy fluid operated servo-.motors.

The principal feature oftherinvention'consists in the-novel arrangement'iofr a pairroftrot'ors withinra' fiuid tight casing with cylinders. individually enclosing :said rotors being 110011111186 w'ithinwsaid casing and fleeing.:SeparateIyinperabIe to alter their axial positions relative-.tothez'rotors enclosed thereby.

'Aafurther feature'of importanc'e consists. in the novel arrangement oflfiuid operated: servomotors for adjusting the. rotori-enclosingnylinders land the means .for 'effec-ting'th'e coeoperative control of said servo-motors.

In the accompanying. drawings :Flgure 1 is :a vertical longitudinal. midi-sectional view of" a :fiuidttransmission.cmrstructed in accordance with this invention.

'EigureZ is a: half end 'elevation'I and half vertical' cross" section throughithel'inachine taken on the line 221of Figurel.

Figure 3 is a vertical cross sectional #view through theidriving rotor *and its enclosing-cylinder "with the cylinder and rotor arranged coaxially in the neutral or non-dfivingposition.

Figure 4 is a vertical cross sectional view through the driven rotor'a-nd its-enclosing cylinder in the eccentric position 'relative'to the driving member when said driving member is in the neutral position.

Figure .5 is a view similar to Figure '3' illustrating the relative eccentric relation ofthecylinder and rotor in a driving.. pos'ition.

.Figure dis a View similar to Figure .4.i-1lustrating the relative .position -of thecylindenand rotor being driven. Figure 7 is a plan viewmfwa portion of the machine showing :the servo-motors for operating the driving and driven rotors and the 1111165115 for'controlling same.

Figure 8' is avertical sectional view taken on the line 8-8 of Figure "7.

Figure-9 isza vertical sectional View taken on the line 98 of Figurefl.

15in the-form ofthe invention herein illustrated a casing I provided with a sealed cover '2 is formed with end journal: bearings B andA and' alignedreentral journal bearings 5 and 6 lmountedinsa. cross member "I.

-Mountedin the journalz=bearings-.-3. and-:5 :is the driving shaft 3, the outer end of which will be connected to: a suitablelprime. moversuch as arr-engine.orelectricanotor.

lldounted the journal vwbearings A-and 6 'is a; xirivenishaitifi, .at the .outert-end. of which'iis connected the mechanism to be driven.

eRigidly secured-.1 n'.the*shaft 8 between its journal bearings: in ?.a-..radialiy i slotted rotor I ll carrying. apluralityaof radial vanes .I l :eachmf which is provided with azcontactshoe i2. rockably. mounted therein.

: A similarrotorr131s? mounted on: the shaft .9. GylindersM-and:I'5- enelose the rotors! and lhveach havi-ngx-lateral vextensions i6 slidably mounted. on :1 horizonal LguideWays l 1 extending transversely within the :casing I. These cylinders 1.! 4 rand :15 and their extensions 16 define with the-casing i and cover :22 andv guideway l I separatedwhigh and:low vpressure passages I4 and 15 *respectively' within the casing as will beseenpfromrFigures' l-and2. I

The-.-cylinder Mcenclosingrthe rotor on the driving shaft :8 is? formed with an intake; port ldtatthe oottomz and"a discharge port IQI'atthe topnand the cylinder l5 is.-formed I with an .:intake portztlvatzthe. topziand a discharge porti I atthe bottom.

The radial vanes of eachzrotor arepreierably supported .fin". their extendedpositions with the contact shoes [lengagingtthe cylinder surfaces.

:The teasing I ::is :for'med 'with: cylindrical hub extensions 22 and 23 having their axes arranged in'the horizontal planerof'and at right angles tothe axis of the shaits'fl-and'il and within each:hub iswa cylinder'chamber .24 which has .a ported-arranged centrally of'the length thereof and which conimunicates with' the high pressure passage W of 'xthe -interiorof the casing l to conduct pressure .fluid.

=iiz1pistontrod 26 is connectedto teach of'ithe retorxrcylinders-i 4' and li which extends through a: su'itably -packedbearingin the. inner'end of the cylinder'iz i'aridlihas'imountedi thereon within saidmylinder :24." apiston' 121. :Thepi'ston 2'! has torrhedinfiits upper side'rnidwa-y of its length a-T-shaped portfl 8- which -e'X-tends inwardly to a longitudinal axial bore :19. Reverse L shaped ports 30 and 3| are arranged either side of the central portion of the T-shaped port 28 and lead outwardly from the central bore 29 to the opposite ends of the piston.

A U-shaped port 32 is arranged in the lower side of the piston, the separated inner ends 33 and 34 being spaced apart a distance wider than the inward ends of the L-ports 30 and 3! and leading from the bore 29 outwardly to a central exhaust port 35 in the cylinder wall which leads to both ends of the cylinder casing, communicating at the inner end with the low pressure passage l of the interior of the casing l and at the other end with an oil duct 36 which encircles the bore 35 of the cylinder head 31.

A piston valve 38 is slidably mounted in the bore 36' of the cylinder head and extends into the bore 29 of the piston 21 and is formed with spaced annular ports 39 and 4!! which normally communicate with the inner ends of the L-ports 3E! and 3! and which lie between the inner ends 33 and 34 of the U-port 32.

An escape port 45 extends from the inner end of the bore 29 to the low pressure passage l5 of the interior of the casing l.

The outward end of the piston rod 88 is formed with a flattened upper face 42 and extendingupwardly therefrom is a pin 43 carrying a roller 44.

Slidably mounted on the bearing member supporting the piston rod 38 which actuates driving unit cylinder !4 is a plate 45 which is formed with a U-shaped slot 45 into which the roller 44 extends.

A block 4! is removably secured in one leg of the U-slot 45 to prevent the roller moving into that leg when the plate is moved transversely to the piston rod.

The plate 45 is operated by a control rod 48 which may be operated manually or by a suitable governor and when moved transversely by pushing on the rod 48 the roller 44 is forced by the inclined surface of the slot, thereby moving the piston valve 33 inwardly.

The inward movement of the valve 38 opens communication between the fluid pressure containing port 28 and the port 39, thereby directing pressure fluid to the outward end of the piston 2! and moving it inwardly to alter the position of the cylinder 14 relative to the rotor III. F

The inward movement of the piston 21 shifts the port 25 relative to the ports 39 and 40 in the piston valve 38 so that the port 28 is again closed and movement of the piston ceases and it is held in the assumed position until the ported piston valve 38 is again moved.

The piston control plate 45 of the driving unit cylinder !4 is connected with a similar slidable plate 49 of the driven unit cylinder l5 by a rod 50.

The plate 49 is formed with a D-shaped slot 5| which is in a reverse position to the U-slot 45 in the plate 45 and the roller 52 operating the piston valve of the driven unit cylinder actuator is in the full inward position when the roller 44 is in the central position.

It will be seen that, due to the relative arrangement oi the U and D-slots in the plates 45 and 49 the movement of the control bar first moves the piston valve and the cylinder [4 of the driving unit from the mid-position to the extreme inward position while the piston valve and the cylinder 15 of the driven unit are held in the extreme position by the position of the roller 52 in the leg of the slot 5|. Continued movement of the control rod then moves the bevelled end of the D-slot 5| to move the roller and piston valve of the driven unit from the extreme position to the mid-position.

Therefore when the cylinder 14 is in the neutral position relative to its rotor l0 when no oil is being pumped, as shown in Figure 3, the cylinder I5 is in the extreme position relative to its rotor l3, requiring as shown in Figure 4 the maximum amount of oil per revolution and no motion is being transmitted to the driven shaft. When the piston valve 38 of the driving member is moved inward the cylinder I4 is shifted to a position as shown in Figure 5, gradually increash'ig the amount of oil pumped per revolution, building up the speed of the driven member. owing to the arrangement of the valve mechanism described when cylinder I4 reaches its extreme position the roller 52 on piston valve 38 will begin to engage the tapered portion of the U-slot 5| which as described above causes the cylinder [5 to be moved from its extreme position, thereby reducing the oil required per revolution as shown in Figure 6 and so further increasing the output speed.

At the mid-travel position of the control bar 45 the driving unit will be delivering a maximum quantity of oil per revolution through its discharge port and the driven member will have the maximum quantity of oil flowing through its intake port.

If the two cylinder units are of equal capacity the driven speed will equal the driving speed but if they are of unequal size, the speed ratio will be inversely proportioned to the relative size.

Movement of the control bar past the point of mid-travel will gradually reduce the amount of oil required per revolution by the driven rotor and the speed of the driven member will be gradually increased.

Provision is made for reversing the direction of rotation of the driven member. The slot 5| is continued across the spaced ends by a passage 53 and slidably mounted adjacent thereto is aplate 54 formed with a forked end 55 which engages the roller pin 52 which may be moved to shift the roller to the opposite or outer branch of the U-slot 5!, thereb reversing the position of the piston valve relative to the servo-motor piston for operating the cylinder I5.

The plate 54 is provided with edge notches 56 and 51 which are engaged by a spring bolt 58 to hold the reversing plate in the adjusted positions.

Reversal of the direction of pumping of the driving rotor Ii] may be effected by shifting the block 47 located in the U-slot 45 to the opposite fork to that shown, thereby changing the direction of discharge flow in the driving member.

It will be appreciated that the control rod 48 and the controlling piston valves operated thereby may be moved with very little eifort so that this mechanism may readily be operated by a simple form of governor or similar device.

A fluid transmission such as described is extremely flexible in its operation. It enables the transmission of speed from the driving to the driven member at varying speeds in a smooth uninterrupted flow and the direction of movement can be instantly changed the accelerated speed being automatically braked by the fluid medium.

The structure of the device is simple and rugged and there are no delicate parts liable to get out of order. Further, as the device operates with oil as the fluid medium all parts will be effectively lubricated.

It will be understood that while a special form of servo-motor for controlling the cylinders relative to their rotors has been described other forms of control devices may be used effectively.

What I claim as my invention is:

1. In a hydraulic power transmission the com bination with a closed casing, a pair of independently operable shafts journalled longitudinally of said casing and having rotors thereon, and cylinders enclosing said rotors and defining with said casing separated passages leading between said cylinders, each of said cylinders having an inlet port communicating with one of said passages and a discharge port communicating with the other of said passages, of cylinders formed in said casing each having intermediate its length an intake port communication with one of said passages and a discharge port communicating with the other of said passages, a piston operating in each of said casing cylinders and operatively connected with one of said rotor cylinders to move same tranversely in said casing, said pistons each having a central bore and a port arranged centrally of its length communicating with the intake port of the cylinder in which it operates and ports arranged each side of said central port leading to the piston ends and a discharge port arrangement communicating with the discharge port of the cylinder in which it operates, a piston valve operable in the central bore of each of said pistons and having ports co-opcrating with said central and end piston ports, the end of each of said piston valves extending beyond its casing cylinder and being provided with a pin extension having a roller mounted thereon, a plate mounted to slide transversely of one of said piston valves having a curved slot therein engaging the roller on the valve pin to first operate the valve in a predetermined direction and then hold it from further movement, a plate mounted to slide transversely of the other of said piston valves and connected to operate with the aforesaid plate and having a slot therein adapted to permit the first movement of the second plate without movement of its valve and to then move the second valve while the first valve is stationary.

2. In a hydraulic power transmission the combination with a closed casing, a pair of independently operable shafts journalled longitudinally of said casing having rotors thereon, and cylinders enclosing said rotors and defining with said casing separated passages leading between said cylinders, each of said cylinders having an inlet port communicating with one of said passages and a discharge port communicating with one of said passages, of cylinders formed in said casing each having intermediate its length an intake port communication with one of said passages and a discharge port communicating with the other of said passages, a piston operating in each of said casing cylinders and operatively connected with one of said rotor cylinders to move same transversely in said casing, said pistons each having a central bore and a port arranged centrally of its length communicating with the intake port of the cylinder in which it operates and ports arranged each side of said central port leading to the piston ends and a discharge port arrangement communicating with the discharge port of the cylinder in which it operates, a piston valve operable in the central bore of each of said pistons and laying ports co-operating with said central and end piston ports, the end of each of said piston valves extending beyond its casing cylinder and being provided with a pin extension, a plate mounted to slide transversely of one of said piston valves having a U-shaped slot engaging the valve pin, a plate mounted to slide transversely of the other of said piston valves having a D-shaped slot therein engaging the pin of said latter valve, and means for shifting said latter valve to move its pin into a different relation to the D-shaped slot to effect a reverse movement of the mechanism .controlled by said latter valve.

ROBERT S. SEGSWORTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 466,660 Duncan Jan. 5, 1892 1,656,544 Thoma Jan. 1'7, 1928 1,762,532 Sorensen June 10, 1930 1,840,869 Rayburn Jan. 12, 1932 2,211,402 Benedek Aug. 13, 1940 2,255,963 Benedek Sept. 16, 1941 2,309,148 Wilson Jan. 26, 1943 2,384,218 Tucker Sept. 4, 1945 2,492,720 Tyler Dec. 27, 1949 FOREIGN PATENTS Number Country Date 222,647 Great Britain Oct. 9, 1924 426,861 Great Britain Apr. 10, 1935 519,686 Germany Mar. 3, 193 1 

